1. Field of Invention
This invention relates to compositions and methods for degrading, removing, and preventing bacterial cellulose deposits. More particularly, this invention relates to enzymatic detergent compositions and methods of using them to degrade, remove, and prevent polymeric bacterial cellulose deposits in aqueous systems such as drain pipes.
2. Description of the Related Art
Traditional approaches to controlling or eliminating the problem of bacterial cellulose build-up in sugar or alcohol enriched drain systems typically have included contacting the cellulose with highly corrosive chemicals, such as concentrated hydrochloric acid, concentrated sulfuric acid, sodium hypochlorite, sodium silicate, chlorine bleach, phenylmercuric acetate, pentachlorophenol, tributyltin oxide, isocyanurates, or sodium hydroxide. However, these treatments have proven ineffective or incapable of removing deposited-cellulosic slime, and they have several drawbacks associated with their use. Most of these chemicals are toxic to many organisms, including humans. Their toxicity makes them very dangerous during handling, and they contaminate and pollute if they are discharged into the environment. In addition to the problems engendered by toxicity, many of these toxic and hazardous chemicals can damage the drain systems where bacterial cellulose deposits are found.
Mechanical water jetting and rotor rooting are nontoxic alternatives to the chemical treatments described above. Of these, water jetting is preferred because it is less likely to cause damage to the drain systems. Yet neither method is an effective, acceptable treatment to prevent or remove bacterial cellulose deposits in drain systems. Bacterial cellulose accumulates rapidly in susceptible drain systems, and to keep such drains completely clear by these mechanical means requires frequent treatments. The frequent interruption in drain service occasioned by jetting or rooting makes them impractical. In addition, both methods involve significant manual labor, adding considerably to the cost of removing the deposits. Their cost and inefficiency make jetting or rooting uneconomical as prophylactic treatments. The result is that many drains having a bacterial cellulose problem are ineffectively and infrequently treated and therefore function at a severely reduced capacity or not at all.
U.S. Pat. No. 5,443,656 to Burrows et al. proposes a process for degrading fibrous cellulose materials, more particularly toilet tissue in aqueous waste holding tanks, by contacting the material with a composition comprising a cellulase enzyme, sodium bicarbonate, and citric acid. However, this method does not use an enzyme having activity specific to polymeric cellulose typically produced by microorganisms such as Acetobacter bacteria, and the enzyme concentrations disclosed are too low for effectively treating cellulose deposited by such microorganisms. Moreover, compositions disclosed in this reference contain large quantities of sodium chloride, which drastically reduces cellulase enzyme activity under the conditions wherein the present invention is applied.
U.S. Pat. No. 3,506,582 to Gertzman discloses enzymatic drain cleaner compositions composed of a metal salt of carbonic acid, glucono-delta-lactone, and a mixture of enzymes, including amylase, protease, lipase, pectinase, and cellulase. These compositions suffer the same drawbacks found in the Burrows patent, i.e., they do not address the polymeric bacterial cellulose substrate produced by microorganisms such as Acetobacter bacteria, and they contain significant amounts of sodium chloride, which inhibits enzyme activity under the conditions where such bacterial cellulose deposits are found. Moreover, the disclosed compositions contain relatively high concentrations of amylase and lipase enzymes specific to degrade starchy, greasy, or fatty materials rather than bacterial cellulose.
U.S. Pat. No. 5,264,146 to Tobiason discloses a method and composition for carrying sewer or drain cleaning agents, including lipase and lipase excreting bacteria, to clean draincs and sewer lines. This reference neither discloses nor suggests using an enzyme having activity specific to the troublesome cellulose deposited in sugar and alcohol enriched environments by microorganisms such as Acetobacter bacteria. Moreover, the disclosed compositions can contain other cleaning agents, including corrosive chemicals such as caustic soda and harmful solvents such as dichlorobenzene.
U.S. Pat. No. 5,407,595 to Kamiya discloses a detergent drain pipe cleaning composition comprising a lipocatabolic lipase, an imbibing agent such as sodium bicarbonate, and an N-acyclic amino acid, but no cellulase enzyme. Thus, this composition also is not specific to cellulose produced by microorganisms such as Acetobacter bacteria, and therefore is not effective to address the problem solved by the present invention.